U.S. patent number 6,636,179 [Application Number 09/546,630] was granted by the patent office on 2003-10-21 for v-type aperture coupled circular polarization patch antenna using microstrip line.
This patent grant is currently assigned to Newcom Electronics Co., Ltd., Jong-Myung Woo. Invention is credited to Byung-Kook Kim, N/A, Jong-Myung Woo.
United States Patent |
6,636,179 |
Woo , et al. |
October 21, 2003 |
V-type aperture coupled circular polarization patch antenna using
microstrip line
Abstract
A V type aperture coupled circular polarization patch antenna
constructed with a microstrip line formed on a rear face of a
dielectric substance, a ground surface formed on an entire face of
the dielectric substance, a V type aperture formed at a desired
angle on the basis of a portion of the ground surface, which
overlaps with the microstrip line, and a patch formed into a
rectangular shape and mounted at an upper portion of the aperture
so as to cover the aperture. At 1.9375 GHz, which is one of center
frequencies of IMT-2000, the reflection loss is -11.34 dB, the band
width at minus 10 dB is 15.2% (295 MHz), the beam width is
60.degree., and a proper circular polarization may be obtained.
Inventors: |
Woo; Jong-Myung, N/A
(Youseong-gu, Taejon, KR), Kim; Byung-Kook (Taejon,
KR) |
Assignee: |
Woo; Jong-Myung (Taejon,
KR)
Newcom Electronics Co., Ltd. (Chungcheongnam-do,
KR)
|
Family
ID: |
19579191 |
Appl.
No.: |
09/546,630 |
Filed: |
April 10, 2000 |
Foreign Application Priority Data
|
|
|
|
|
Apr 8, 1999 [KR] |
|
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99-12416 |
|
Current U.S.
Class: |
343/700MS;
343/830; 343/848 |
Current CPC
Class: |
H01Q
9/0428 (20130101); H01Q 9/0457 (20130101) |
Current International
Class: |
H01Q
9/04 (20060101); H01Q 001/38 () |
Field of
Search: |
;343/7MS,848,846,830,767,795,872,713,829,771,770,768,725,729,853 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Wong; Don
Assistant Examiner: D; Chuc Tran
Attorney, Agent or Firm: Bushnell, Esq.; Robert E.
Claims
What is claimed is:
1. A V type aperture coupled circular polarization patch antenna,
comprising: a microstrip line formed on a rear face of a dielectric
substance; a ground surface formed on an entire face of the
dielectric substance; a V type aperture formed at an angle
established on a basis of a portion of the ground surface
overlapping with the microstrip line; and a a patch formed into a
rectangular shape and mounted at an upper portion of the aperture
so as to cover the aperture.
2. The antenna of claim 1, wherein said angle is 90.degree..
3. A V type aperture coupled circular polarization patch antenna,
comprising: a microstrip line which is formed on a rear face of a
dielectric substance; a ground surface which is formed on an entire
face of the dielectric substance; a V type aperture which is formed
at a desired angle on the basis of a portion of the ground surface,
which overlaps with the microstrip line; and a patch formed into a
rectangular shape, mounted at an upper portion of the aperture so
as to cover the aperture, and having a long side and a short side,
each length of the long and short sides of the patch being adjusted
to provide a phase difference of 90.degree. according to a mutual
impedance.
4. A V type aperture coupled circular polarization patch antenna,
comprising: a microstrip line which is formed on a rear face of a
dielectric substance; a ground surface which is formed on an entire
face of the dielectric substance; a V type aperture which is formed
at a desired angle on the basis of a portion of the ground surface,
which overlaps with the microstrip line, and which has a size and a
length adjusted so as to have a phase difference of 90.degree.
according to a mutual impedance; and a patch which is formed into a
rectangular shape and is mounted at an upper portion of the
aperture so as to cover the aperture.
5. In a mobile, aperture-coupled, circular-polarization antenna
device adapted for reception of signals in satellite-based vehicle
communication, said antenna device comprising: a dielectric
substrate having an upper planar surface and, parallel thereto and
spaced therefrom, a lower planar surface; a microstrip line
disposed on the lower surface of the dielectric substrate; a ground
plane comprising a conductive coating covering the upper surface of
the dielectric substrate; an aperture formed in the ground plane:
by removal therefrom of a predetermined portion of the conductive
coating, said aperture having a predetermined size, shape, and
orientation; and a patch mounted above the aperture and completely
covering the aperture, said patch having a predetermined size,
shape, and orientation, the improvement comprising: a means for
maintaining a constant level of signal reception in the antenna
device regardless of successive movements of the antenna device in
different directions.
6. The antenna device of claim 5, wherein said means comprises
configuration of the predetermined size, shape, and orientation of
the aperture and configuration of the predetermined size, shape,
and orientation of the patch in a manner such that a constant level
of signal reception in the antenna device is maintained regardless
of successive movements of the antenna device in different
directions.
7. The antenna device of claim 5, wherein said aperture consists of
a single chevron-shaped slot having a first slot segment
longitudinally extending in a first direction, said first slot
having an inner end at a central portion of the ground plane and an
outer end distanced from the central portion of the ground plane;
and having a second slot segment longitudinally extending in a
second direction, said second slot having an inner end at the
central portion of the ground plane and an outer end distanced from
the central portion of the ground plane; said first and second slot
segments joined at the inner ends thereof.
8. The antenna device of claim 7, wherein said first direction is
orthogonal to said second direction.
9. The antenna device of claim 8, wherein said patch is rectangular
and has a length oriented in the first direction and a width
oriented in the second direction.
10. In a mobile, aperture-coupled, circular-polarization antenna
device adapted for reception of signals in satellite-based vehicle
communication, said antenna device comprising: a dielectric
substrate having an upper planar surface and, parallel thereto and
spaced therefrom, a lower planar surface; a microstrip line
disposed on the lower surface of the dielectric substrate; a ground
plane comprising a conductive coating covering the upper surface of
the dielectric substrate; an aperture formed in the ground plane by
removal therefrom of a predetermined portion of the conductive
coating, said aperture having a predetermined size, shape, and
orientation; and a rectangular patch mounted above the aperture and
completely covering the aperture, said patch having a predetermined
size, shape, and orientation; the improvement comprising: a means
for maintaining a constant level of signal reception in the antenna
device regardless of successive movements of the antenna device in
different directions, said means comprising configuration of the
predetermined size, shape, and orientation of the aperture and
configuration of the predetermined size, shape, and orientation of
the rectangular patch in a manner such that a constant level of
signal reception in the antenna device is maintained regardless of
successive movements of the antenna device in different directions,
said rectangular patch having a length oriented in a first
direction and a width oriented in a second direction orthagonal to
said first direction, said aperture consisting of a single
chevron-shaped slot having: a first slot segment longitudinally
extending in said first direction, said first slot having an inner
end at a central portion of the ground plane and an outer end
distanced from the central portion of the ground plane; a second
slot segment longitudinally extending in said second direction,
said second slot having an inner end at the central portion of the
ground plane and an outer end distanced from the central portion of
the ground plane; said first and second slot segments joined at the
inner ends thereof; the first slot segment having a first slot
length; the second slot segment having a second slot length; said
first and second slot lengths adjusted to provide a phase
difference of 90.degree. according to mutual impedance; and the
length and width of the patch adjusted to provide a phase
difference of 90.degree. according to mutual impedance.
11. The antenna device of claim 10, replicated four times, to
provide a square array of four antenna devises, whereby a circular
polarization array antenna system is provided.
12. The antenna device of claim 10, replicated four times to
provide a square array of four antenna devices, and coupled to a
phase transformation device for transforming respectively phases of
three of the antenna devices on the basis of the fourth antenna
device, whereby a circular polarization antenna system is provided
which is adapted for electrical beam scanning and for connection to
a satellite to maintain a maximum receiving level among a plurality
of satellites always revolving on the same hemispherical side of
the Earth.
13. In a method for manufacturing a mobile, aperture-coupled,
circular-polarization antenna device adapted for reception of
signals in satellite-based vehicle communication, said method
comprising the steps of: (1) providing a dielectric substrate
having an upper planar surface and, parallel thereto and spaced
therefrom, a lower planar surface, (2) disposing a microstrip line
on the lower surface of the dielectric substrate; (3) covering the
upper surface of the dielectric substrate with a conductive coating
to provide a ground plane; (4) forming an aperture in the ground
plane by removal therefrom of a predetermined portion of the
conductive coating, said aperture having a predetermined size,
shape, and orientation; and (5) mounting a patch above the aperture
and completely covering the aperture, said patch having a
predetermined size, shape, and orientation; the improvement
comprising configuring the predetermined size, shape, and
orientation of the aperture, and configuring the predetermined
size, shape, and orientation of the patch, in a manner such that a
constant level of signal reception in the antenna device is
maintained regardless of successive movements of the antenna device
in different directions.
14. In a method for manufacturing a mobile, aperture-coupled,
circular-polarization antenna device adapted for reception of
signals in satellite-based vehicle communication, said method
comprising the steps of: (1) providing a dielectric substrate
having an upper planar surge and, parallel thereto and spaced
therefrom, a lower planar surface; (2) disposing a microstrip line
on the lower surface of the dielectric substrate; (3) covering the
upper surface of tie dielectric substrate with a conductive coating
to provide a ground plane; (4) forming an aperture in the ground
plane by removal therefrom of a predetermined portion of the
conductive coating, said aperture having a predetermined size,
shape, and orientation; and (5) mounting a patch above the aperture
and completely covering the aperture, said patch having a
predetermined size, shape, and orientation; the improvement
comprising providing means, embodied in the respective
predetermined sizes, shapes, and orientations of the aperture and
patch, for maintaining a constant level of signal reception in the
antenna device regardless of successive movements of the antenna in
different directions.
15. The method of claim 14, wherein said aperture consists of a
single chevron-shaped slot having a first slot segment
longitudinally extending in a first direction, said first slot
having an inner end at a central portion of the ground plane and an
outer end distanced from the central portion of the ground plane;
and having a second slot segment longitudinally extending in a
second direction, said second slot having an inner end at the
central portion of the ground plane and an outer end distanced from
the central portion of the ground plane; said first and second slot
segments joined at the inner ends thereof.
16. The method of claim 15, wherein said first direction is
orthogonal to said second direction.
17. The method of claim 16, wherein said patch is rectangular and
has a length oriented in the first direction and a width oriented
in the second direction.
18. In a method for manufacturing a mobile, aperture-coupled,
circularpolarization antenna device adapted for reception of
signals in satellite-based vehicle communication, said method
comprising the steps of: (1) providing a dielectric substrate
having an upper planar surface and, parallel thereto and spaced
therefrom, a lower planar surface; (2) disposing a microstrip line
on the lower surface of the dielectric substrate; (3) covering the
upper surface of the dielectric substrate with a conductive coating
to provide a ground plane; (4) forming an aperture in the ground
plane by removal therefrom of a predetermined portion of the
conductive coating, said aperture having a predetermined size,
shape, and orientation; and (5) mounting a rectangular patch above
the aperture and completely covering the aperture, said patch
having a predetermined size, shape, and orientation; the
improvement comprising providing means, embodied in the respective
predetermined sizes, shapes, and orientations of the aperture and
rectangular patch, for maintaining a constant level of signal
reception in the antenna device regardless of successive movements
of the antenna in different directions, said means comprising
configuration of the predetermined size, shape, and orientation of
the aperture and configuration of the predetermined size, shape,
and orientation of the rectangular patch in a manner such that a
constant level of signal reception in the antenna device is
maintained regardless of successive movements of the antenna device
in different directions, said rectangular patch having a length
oriented in a first direction and a width oriented in a second
direction orthogonal to said first direction, said aperture
consisting of a single chevron-shaped slot having: a first slot
segment longitudinally extending in said first direction, said
first slot having an inner end at a central portion of the ground
plane and an outer end distanced from the central portion of the
ground plane; a second slot segment longitudinally extending in
said second direction, said second slot having an inner end at the
central portion of the ground plane and an outer end distanced from
the central portion of the ground plane; said first and second slot
segments joined at the inner ends thereof; the first slot segment
having a first slot length; the second slot segment having a second
slot length; said first and second slot lengths adjusted to provide
a phase difference of 90.degree. according to mutual impedance; and
the length and width of the patch adjusted to provide a phase
difference of 90.degree. according to mutual impedance.
19. A method for maintaining constancy of signal reception level by
a mobile antenna device, despite variations in motion of the
antenna device, said method comprising the steps of: (1) providing
a dielectric substrate having an upper planar surface and, parallel
thereto and spaced therefrom, a lower planar surface; (2) disposing
a microstrip line disposed on the lower surface of the dielectric
substrate; (3) covering the upper surface of the dielectric
substrate with a conductive coating to provide a ground plane; (4)
forming an aperture in the ground plane by removal therefrom of a
predetermined portion of the conductive coating, said aperture
having a predetermined size, shape, and orientation; and (5)
mounting a patch above the aperture and completely covering the
aperture, said patch having a predetermined size, shape, and
orientation; wherein said aperture and said patch are sized,
shaped, and oriented in a manner such that a constant level of
signal reception in the antenna device is maintained regardless of
successive movements of the antenna device in different
directions.
20. A method for maintaining constancy of signal reception level by
a mobile antenna device, despite variations in motion of the
antenna device, said method comprising the steps of: (1) providing
a dielectric substrate having an upper planar surface and, parallel
thereto and spaced therefrom, a lower planar surface; (2) disposing
a microstrip line disposed on the lower surface of the dielectric
substrate; (3) covering the upper surface of the dielectric
substrate with a conductive coating to provide a ground plane; (4)
forming an aperture in the ground plane by removal therefrom of a
predetermined portion of the conductive coating, said aperture
having a predetermined size, shape, and orientation; (5) mounting a
patch above the aperture and completely covering the aperture, said
patch having a predetermined size, shape, and orientation; and (6)
providing the device with a means for maintaining a constant level
of signal reception therein regardless of successive movements
thereof in different directions.
21. The method of claim 20, wherein said aperture consists of a
single chevron-shaped slot having a first slot segment
longitudinally extending in a first direction, said first slot
having an inner end at a central portion of the ground plane and an
outer end distanced from the central portion of the ground plane;
and having a second slot segment longitudinally extending in a
second direction, said second slot having an inner end at the
central portion of the ground plane and an outer end distanced from
the central portion of the ground plane; said first and second slot
segments joined at the inner ends thereof.
22. The method of claim 21, wherein said first direction is
orthogonal to said second direction.
23. The method of claim 22, wherein said patch is rectangular and
has a length oriented in the first direction and a width oriented
in the second direction.
24. A method for maintaining constancy of signal reception level by
a mobile antenna device, despite variations in motion of the
antenna device, said method comprising the steps of: (1) providing
a dielectric substrate having an upper planar surface and, parallel
thereto and spaced therefrom, a lower planar surface; (2) disposing
a microstrip line disposed on the lower surface of the dielectric
substrate; (3) covering the upper surface of the dielectric
substrate with a conductive coating to provide a ground plane; (4)
forming an aperture in the ground plane by removal therefrom of a
predetermined portion of the conductive coating, said aperture
having a predetermined size, shape, and orientation; (5) mounting a
rectangular patch above the aperture and completely covering the
aperture, said patch having a predetermined size, shape, and
orientation; and (6) providing the device with a means for
maintaining a constant level of signal reception therein regardless
of successive movements thereof in different directions, said means
comprising configuration of the predetermined size, shape, and
orientation of the aperture and configuration of the predetermined
size, shape, and orientation of the rectangular patch in a manner
such that a constant level of signal reception in the antenna
device is maintained regardless of successive movements of the
antenna device in different directions, said rectangular patch
having a length oriented in a first direction and a width oriented
in a second direction orthogonal to said first direction, said
aperture consisting of a single chevron-shaped slot having: a first
slot segment longitudinally-extending in said first direction, said
first slot having an inner end at a central portion of the ground
plane and an outer end distanced from the central portion of the
ground plane; a second slot segment longitudinally extending in
said second direction, said second slot having an inner end at the
central portion of the ground plane and an outer end distanced from
the central portion of the ground plane; said first and second slot
segments joined at the inner ends thereof; the first slot segment
having a first slot length; the second slot segment having a second
slot length; said first and second slot lengths adjusted to provide
a phase difference of 90.degree. according to mutual impedance; and
the length and width of the patch adjusted to provide a phase
difference of 90.degree. according to mutual impedance.
25. A method for receiving communication signals at a substantially
constant signal reception level, in a antenna system subject to
being successively moved in different directions, said method
comprising the steps of; (1) receiving radiated communication
signals via a vertical radiating antenna connected to a conductive
plate; (2) coupling the radiated communication signals through a
device comprising: a dielectric substrate having an upper planar
surface and, parallel thereto and spaced therefrom, a lower planar
surface; a microstrip line disposed on the lower surface of the
dielectric substrate; a ground plane comprising a conductive
coating covering the upper surface of the dielectric substrate; an
aperture formed in the ground plane by removal therefrom of a
predetermined portion of the conductive coating, said aperture
having a predetermined size, shape, and orientation; a patch
mounted above the aperture and completely covering the aperture,
said patch having a predetermined size, shape, and orientation; and
a means for maintaining a constant level of signal reception in the
antenna regardless of successive movements of the antenna in
different directions; and (3) coupling the signals from the
microstrip to a transmission line connected to a communications
receiver device.
26. The method of claim 25, wherein said aperture consists of a
single chevron-shaped slot having a first slot segment
longitudinally extending in a first direction, said first slot
having an inner end at a central portion of the ground plane and an
outer end distanced from the central portion of the ground plane;
and having a second slot segment longitudinally extending in a
second direction, said second slot having an inner end at the
central portion of the ground plane and an outer end distanced from
the central portion of the ground plane; said first and second slot
segments joined at the inner ends thereof.
27. The method of claim 26, wherein said first direction is
orthogonal to said second direction.
28. The method of claim 27, wherein said patch is rectangular and
has a length oriented in the first direction and a width oriented
in the second direction.
29. A method for receiving communication signals at a substantially
constant signal reception level, in a antenna system subject to
being successively moved in different directions, said method
comprising the steps of: (1) receiving radiated communication
signals via a vertical radiating antenna connected to a conductive
plate; (2) coupling the radiated communication signals through a
device comprising: a dielectric substrate having an upper planar
surface and, parallel thereto and spaced therefrom, a lower planar
surface; a microstrip line disposed on the lower surface of the
dielectric substrate; a ground plane comprising a conductive
coating covering the upper surface of the dielectric substrate; an
aperture formed in the ground plane by removal therefrom of a
predetermined portion of the conductive coating, said aperture
having a predetermined size, shape, and orientation; a rectangular
patch mounted above the aperture and completely covering the
aperture, said patch having a predetermined size, shape, and
orientation; and a means for maintaining a constant level of signal
reception in the antenna regardless of successive movements of the
antenna in different directions, said means comprising
configuration of the predetermined size, shape, and orientation of
the aperture and configuration of the predetermined size, shape,
and orientation of the rectangular patch in a manner such that a
constant level of signal reception in the antenna device is
maintained regardless of successive movements of the antenna device
in different directions, said rectangular patch having a length
oriented in a first direction and a width oriented in a second
direction orthagonal to said first direction, said aperture
consisting of a single chevron-shaped slot having: a first slot
segment longitudinally extending in said first direction, said
first slot having an inner end at a central portion of the ground
plane and an outer end distanced from the central portion of the
ground plane; a second slot segment longitudinally extending in
said second direction, said second slot having an inner end at the
central portion of the ground plane and an outer end distanced from
the central portion of the ground plane; said first and second slot
segments joined at the inner ends thereof; the first slot segment
having a first slot length; the second slot segment having a second
slot length; said first and second slot lengths adjusted to provide
a phase difference of 90.degree. according to mutual impedance; and
the length and width of the patch adjusted to provide a phase
difference of 90.degree. according to mutual impedance; and (3)
coupling the signals from the microstrip to a transmission line
connected to a communications receiver device.
30. A method of electrical beam scanning to maintain a maximum
receiving level among a plurality of satellites always revolving on
the same hemispherical side of the Earth, said method comprising
the steps of: (1) providing four antenna devices, each of said
devices comprising: a dielectric substrate having an upper planar
surface and, parallel thereto and spaced therefrom, a lower planar
surface; a microstrip line disposed on the lower surface of the
dielectric substrate; a ground plane comprising a conductive
coating covering the upper surface of the dielectric substrate; an
aperture formed in the ground plane by removal therefrom of a
predetermined portion of the conductive coating, said aperture
having a predetermined size, shape, and orientation; and a patch
mounted above the aperture and completely covering the aperture,
said patch having a predetermined size, shape, and orientation, the
respective predetermined sizes, shapes, and orientations of said
aperture and patch configured in a manner such that a constant
level of signal reception in the antenna device is maintained
regardless of successive movements of the antenna device in
different directions; (2) arranging the four antenna devices in a
square array; (3) coupling the antenna devices to a phase
transformation device for transforming respectively phases of three
of the antenna devices on the basis of the fourth antenna device;
and (4) pointing the array at a one of the satellites.
Description
CLAIM OF PRIORITY
This application makes reference to, incorporates the same herein,
and claims all benefits accruing under 35 U.S.C. .sctn.119 from my
application V-TYPE APERTURE COUPLED CIRCULAR POLARIZATION PATCH
ANTENNA USING MICROSTRIP LINE filed with the Korean Industrial
Property Office on the 8.sup.th day of April 1999 and there duly
assigned Ser. No. 12416/1999.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to satellite-based vehicle
communication with a PCS base station and a satellite broadcasting
receiver, and, more particularly, to a communication process and
V-type aperture coupled circular polarization patch antenna using a
microstrip line.
2. Description of the Related Art
Generally, a precise polarization adjustment is needed in a
communication system in order to optimize the system and its
operational functioning. There are various kinds of polarizations,
including linear polarization, circular polarization and elliptical
polarization. The design of polarization should be properly
selected and used in conformity with the particular system in which
the design is being applied. In a vehicle-mounted satellite
communication system for example, it is preferable that
polarization, which is independent of the moving direction of the
vehicle, is used in order to maximize reception of electric waves
from the satellite without fluctuation in the level of reception.
Therefore, in satellite-based vehicle communication systems, the
circular polarization is used in an effort to maintain a constant
level of reception, regardless of the direction of movement of the
vehicle.
Circular polarization can be produced only when two linear
polarizations, which determine the direction of polarization, have
the same amplitude and are orthogonal to each other so as to assure
a relative phase difference of 90.degree.. A microstrip patch
antenna is adequate to satisfy these circular polarization
generating conditions as well being suitable for mounting upon a
vehicle. That is, the microstrip patch antenna is so thin as to
create negligible air resistance and can be mass-produced by
contemporary printing technology. Typically, the current
distribution provided by the aperture formed in the circular patch
of the antenna will be vectorially distributed at an interval of
90.degree., so that two frequencies radiated by linear differences
in the lengths of the components of the aperture resonate. The
impedances created by these differences in length, for example, the
differences in length between protrusions from the circumference of
the circular patch and an inner diameter of the patch, or
alternatively, between protrusions and recesss, provide a phase
difference of 90.degree. necessary to create a circular
polarization generating conditions. I have found that there are
some problems with conventional circular polarization patch
antennas however, because the design of these antennas are complex
and the manufacturing process is therefore unduly complicated.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide an
improved process and aperture antenna.
It is another object to provide an aperture coupled circular
polarization patch antenna using a microstrip line.
It is still another object to provide a simple design and easily
executed process for manufacturing an aperture antenna.
It is yet another object to provide an aperture coupled circular
polarization patch antenna using a microstrip line, in which the
microstrip line and a patch are separated by a ground surface so
that an active device is mounted on the feeding line to be capable
of beam scanning of an array antenna.
It is still yet another object to provide a microstrip patch
antenna that is adequate to satisfy these circular polarization
generating conditions while being suitable for mounting upon a
vehicle.
It is a further object to provide a microstrip patch antenna that
is thin enough to create negligible air resistance and may be
easily mass-produced by contemporary printing technology.
These and other objects may be achieved in the practice of the
present invention, with a V type aperture coupled circular
polarization patch antenna constructed with a microstrip line that
is formed on a rear face of a dielectric substance, a ground
surface that is formed on an entire face of the dielectric
substance, a V type aperture that is formed at a desired angle on
the basis of a portion of the ground surface, and which overlaps
with the microstrip line, and a patch that is formed into a
rectangular shape and is mounted at an upper portion of the
aperture so as to cover the aperture. Preferably, the V type
aperture is formed at an angle of 90.degree., with each length of
the long and short sides of the patch being adjusted to provide a
phase difference of 90.degree. according to mutual impedance, and
size and length of the aperture being adjusted so as to have a
phase difference of 90.degree. according to the mutual
impedance.
BRIEF DESCRIPTION OF THE DRAWINGS
A more complete appreciation of the invention, and many of the
attendant advantages thereof, will be readily apparent as the same
becomes better understood by reference to the following detailed
description when considered in conjunction with the accompanying
drawings in which like reference symbols indicate the same or
similar components, wherein:
FIGS. 1A and 1B are schematic views showing microstrip circular
polarization patch antennas;
FIG. 2A is a plan view showing a structure of a V type circular
polarization patch antenna using a microstrip line constructed
according to the principles of the present invention;
FIG. 2B is a side elevational view showing a structure of a V type
circular polarization patch antenna using a microstrip line
constructed according to the principles of the present
invention;
FIG. 3 is a graph illustrating a principle for generating circular
polarization of an antenna during the practice of the present
invention;
FIGS. 4A and 4B are graphs showing the features of impedance and
reflection loss by an antenna during the practice of the present
invention; and
FIGS. 5A and 5B are graphs showing the features of axial ration and
radiative pattern of an antenna during the practice of the present
invention;
FIG. 6 is a perspective view illustrating an antenna system of the
present application wherein four structures of a V type circular
polarization patch antenna are arranged.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Turning now to the drawings and referring to FIGS. 1A and 1B, a
conventional circular polarization patch antenna 8a or 8b,
respectively, may be made with a strip, or a microstrip 3, and a
circular patch 2. As shown in FIG. 1A, at the circumferential
portions of patch 2 which defines angles of 45.degree. with the
imaginary centerline of a linear aperture 1 formed on a ground
surface 4, there are provided a pair of diametrically opposite
protrusions 5 that project radially outwardly to an outer side of
circular patch 2, in radial directions. In FIG. 1B, at a portion of
patch 2 which defines angles of 45.degree. with respect to the
imaginary centerline of linear aperture 1 that is formed on a
ground surface 4, a pair of diametrically opposite protrusions 5
are formed to extend radially outwardly from the circumference of
patch 2. At diametrically opposite locations on the circumference
of circular patch 2 that are at right angles with protrusions 5,
there is formed a pair of diametrically opposite recesses 6 which
are sunk in radially inward directions into the circumferential
side of patch 2. Therefore, patch 2 has a longer diameter between
the two diametrically opposite protrusions 5 and a shorter diameter
between the two diametrically opposite recesses 6. The current
distribution created by aperture 1 is vectorially distributed at an
interval of 90.degree. so that two frequencies propagated by the
longer and shorter diameters resonate. Moreover, the impedances
created by the differences in length in the embodiment illustrated
in FIG. 1A between the diameter of protrusion 5 and an inner
diameter of the circumference of patch 2, or alternatively, in the
embodiment illustrated by FIG. 1B between the diameter of
protrusion 5 and the lesser diameter of recess 6, is adapted to
provide a phase difference of 90.degree., thereby satisfying the
circular polarization generating conditions. I have found however,
that there are serious problems in the manufacture of these
circular polarization patch antennas because the design of the
antenna is complex, a factor that makes the manufacturing process
unduly complicated.
Turning now to FIGS. 2A and 2B, reference will now be made in
detail to particular embodiments of the present invention, examples
of which are illustrated in the accompanying drawing. A V type
circular polarization patch antenna 20 may be constructed according
to the principles of the present invention by using an elongated
strip or microstrip line 13 formed on one surface of a dielectric
substrate 10. As shown in FIGS. 2A and 2B, there is provided a
strip or microstrip line 13 on the rear face of dielectric
substrate 10. A ground surface 14 forms a ground plane that extends
over an entire front face of the dielectric substance 10.
Dielectric substrate 10 and the overlying ground plane 14 may be
coextensive in their adjoining surface areas, and may be
rectangular in shape. A V shaped aperture 11 is formed with an
orientation established on the basis of a center line "X" of the
ground surface 14. Aperture 11 which is formed by partially
removing the conducting material from both legs 11a, 11b of ground
surface 14. Preferably, each leg 11a, 11b of the V shaped aperture
11 is at an angle of 45.degree. with center line "X", and each leg
11a, 11b forms an angle of 90.degree. with respect to each other.
In addition, a patch 12 is mounted over an upper portion of the
aperture 11 to completely cover aperture 11.
According to the principles of the present invention, when power is
fed through the strip or microstrip line 13, an electromagnetic
field that is excited within aperture 11 is further coupled to
patch 12 which is mounted over the upper portion of aperture 11 and
has a thickness of one half of the wavelength of the power that is
fed via stripline 13, so that a radio wave is radiated according to
the Fringe effect. Here, since the aperture 11 on the ground
surface 14 is formed into the V shape and the patch 12, which is
mounted over the upper portion of the aperture 11, is formed into a
rectangular shape, the electromagnetic field coupled at a center
portion of the aperture 11 is distributed to the right and left
apertures 11a, 11b at an angle of 90.degree. to each other.
Therefore, the electromagnetic fields excited in the patch 12 are
at right angles each other. Also, the lengths of a longer and
shorter sides of patch 12 are properly adjusted so as to provide a
phase difference of 90.degree. according to their mutual impedance,
thereby assuring generation of circular polarization.
In other words, as shown in FIG. 3, a resonance frequency coupled
from the shaped aperture 11 is f.sub.rA in the direction of the
longer side direction of patch 12, and f.sub.rD in the direction of
the shorter side of path 12. If the size of each aperture 11a, 11b
is the same, the coupling coefficients between each aperture 11a,
11b will also be same. Current vectors corresponding to the two
resonance frequencies have the same magnitude and are at right
angles to each other.
Although apertures 11a, 11b are asymmetrical with respect to each
other, the size and length of the apertures 11a, 11b may be
adjusted so as to provide a phase difference of 90.degree. caused
by their mutual impedance. Therefore, the circular polarization
generating conditions may be satisfied by adjustment of the sizes
and.lengths of apertures 11a, 11b, and by adjustment between the
lengths of and the longer and shorter sides of patch 12.
If four antennas constructed according to the principles of the
present invention are arranged in an array with a regular square
shape, the antenna is effectively enlarged into a circular
polarization array antenna with a beam width of 38.degree..
Moreover, if a phase transformation device, which can transform
respectively phases of three antennas on the basis of one antenna,
is provided on a feeding line, a circular polarization antenna may
be created that is capable of electrical beam scanning so as to
connect with a satellite which maintains a maximum receiving level
among about three satellites that are always revolving on the same
hemispherical side of the earth.
FIGS. 4A and 4B show an impedance feature and reflection loss for
an antenna constructed according to the principles of the present
invention. The design is set on the basis of 1.9375 GHz, which is
one of center frequencies of IMT-2000. As a result, the reflection
loss is -11.34 dB, the impedance feature is 32.6-j14.6 .OMEGA., the
band width for minus 10 dB is 15.2% (295 MHz), and the beam width
is 60.degree.. It is shown a comparative wide band by the two
resonance frequencies.
FIGS. 5A and 5B are graphs showing the features of an axial ratio
and a radiative pattern of the antenna constructed according to the
principles of the present invention. When the antenna is rotated by
15 degrees in the azimuthal direction, the radiative pattern is
measured seven times. As the result, the beam width for -3 dB is
about 60.degree.. The posterior lobe pattern differs according to
the rotational angle of the antenna, and maximally indicates up to
-10 dB around 180.degree.. The axial ratio is below 1.7 decibels at
1.9375 Ghz. A proper circular polarization is obtained with this
embodiment.
Referring to FIG. 6, FIG. 6 shows an antenna system wherein four
structures of a V type circular polarization patch antenna
according to the present invention are arranged in a square array
to provide a circular polarization array antenna.
According to the V type aperture coupled circular polarization
patch antenna, there are some advantages because the design for
making the antenna is simplified and the manufacturing process is
thereby facilitated, and the microstrip line and a patch are
separated by a ground surface so that an active device may be
mounted on the feed line in order to be capable of providing beam
scanning for an antenna array.
It will be apparent to those skilled in the art that the details
discussed in the foregoing paragraphs describe a circular
polarization patch antenna that uses a microstrip line to enable
satellite-based vehicle communication with a PCS base station and a
satellite broadcasting receiver. The antenna has a thin planar
structure that facilitates mass production, and is provided with a
V-shaped aperture and a rectangular patch. Various modifications
and variations of the present invention can be made without
departing from the spirit or scope of the invention. Thus, it is
intended that the present invention cover the modifications and
variations of this invention provided they come within the scope of
the appended claims and their equivalents.
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